5322625-UIM-A-0417
Johnson Controls Unitary Products
11
4.
All piping should be cleaned of dirt and scale by hammering on the
outside of the pipe and blowing out the loose dirt and scale. Before
initial start-up, be sure that all of the gas lines external to the unit
have been purged of air.
5.
The gas supply should be a separate line and installed in accor-
dance with all applicable safety codes. After the gas connections
have been completed, open the main shut-off valve admitting nor-
mal gas pressure to the gas valve. Check all joints for leaks with
soap solution or other material suitable for the purpose. NEVER
USE AN OPEN FLAME.
6.
The furnace and its equipment shutoff valve must be disconnected
from the gas supply system during and pressure testing of that sys-
tem at test pressures in excess of 1/2 psi (3.48 kPA)
7.
The furnace must be isolated from the gas supply piping system by
closing its individual manual shut-off valve before conducting any
pressure testing of the gas supply piping system at test pressures
equal to or less than 1/2 psig (3.48 kPa).
HIGH ALITITUDE GAS CONVERSION
This furnace is constructed at the factory for natural gas-fired operation
at altitudes up to 2,000 feet above sea level. For installations located
above 2,000 feet, the gas input rate to the burners must be reduced by
4% per 1,000 feet above sea level. It may be necessary to change to
smaller orifices at high altitude. Refer to the table below for the correct
orifice size to use.
FLUE VENT AND AIR INTAKE HOOD
The flue vent hood and air intake hoods are shipped loose. These hoods
must be installed to assure proper unit operation. The hoods must be fas-
tened to the outside of the side gas control/electrical compartment with
the screws provided. See Figure 8.
Table 8:
Propane (LP) Gas Pipe Sizing Chart
1
1. Maximum capacity of pipe in thousands of BTU per hour (based upon a
pressure drop of 0.5 inch water column).
Length
In Feet
Nominal Inches Iron Pipe Size
1/2”
3/4”
1”
1-1/4”
10
275
567
1071
2,205
20
189
393
732
1496
30
152
315
590
1212
40
129
267
504
1039
50
114
237
448
913
60
103
217
409
834
70
96
196
378
771
80
89
185
346
724
90
83
173
322
677
100
78
162
307
630
CAUTION
If flexible stainless steel tubing is allowed by the authority having
jurisdiction, wrought iron or steel pipe must be installed at the gas
valve and extend a minimum of two (2) inches outside of the unit cas-
ing.
WARNING
Natural gas may contain some propane. Propane being an excellent
solvent, will quickly dissolve white lead or most standard commercial
compounds. Therefore, a special pipe thread sealant must be
applied when wrought iron or steel pipe is used. Shellac base com-
pounds such as gaskoloc or stalastic, and compounds such as Rec-
torseal # 5, Clyde’s or John Crane may be used.
!
!
WARNING
FIRE OR EXPLOSION HAZARD
Failure to follow the safety warning exactly could result in serious
injury, death or property damage.
Never test for gas leaks with an open flame. use a commercially
available soap solution made specifically for the detection of leaks to
check all connections. A fire or explosion may result causing property
damage, personal injury or loss of life.
!
Table 9:
High Altitude Gas Orifice Sizing
ELEVATION ABOVE SEA LEVEL (FEET)
GAS TYPE
0-2000 (FACTORY)
2001-3000
3001-4000
4001-5000
5001-6000
6001-7000
7001-8000
8001-9000
9001-10000
NATURAL GAS
ORIFICE SIZES
36
37
38
38
39
40
41
41
42
42
42
43
43
43
44
44
45
46
LP GAS
ORIFICE SIZES
54
54
55
55
55
55
55
56
56
51
51
52
52
52
52
53
53
53
WARNING
Flue hood surfaces may be hot.
CAUTION
The flue exhaust hood must be properly installed and within the rec-
ommended clearances. Further communications and action must be
given to the home or building owner(s) to eliminate any unauthorized
human contact around this area during the heating cycle. Flue hood
surfaces and the immediate area reach high temperatures during the
heating cycle.
!
!
FIGURE 8:
Flue Vent Outlet Air Hood
AIR INTAKE HOOD
AIR INTAKE SCREEN
EXHAUST HOOD
A0284-001
